Continuous process for clarifying creosote oils



May 1, 1956 P: E. MAYER CONTINUOUS PROCESS FOR CLARIFYING CREOSOTE OILSFiled Sept. 25, 1952 TOWER 2/ OVERFLOW PIPE CREOSOTE WATER- WATER TSLURRY OUTLET CREOSOTE OIL OVERFLOW PIPE CREOSOTE on. /D!SCHARGE DRAINCLARIFIED C REOSOTE OIL TANK CREOS OTE .OIL DISCHARGE INVENTOR. PERRY E.MAYER ATTO R N EY.

United States Patent 0,

1 r 2,744,059 CONTINUOUS PROCESS FOR CLARIFYING 'cnaosorn o1Ls Perry E.Mayer, Audubon, Camden, N. J., assignor to Allied Chemical & DyeCorporation, New York, N. Y., a corporation of New York ApplicationSeptember 23, 1952, Serial No. 311,090

5 Claims. (Cl. 196-146) This invention relates to aprocessfor clarifyingcreosote oils, and more particularly to a process for preparing creosoteoils which will remain'liquid during storage and shipment under normalindustrial conditions. i

I The so-called Creosote oils include, in general, distillates of coalgas tar and coke oven tar, and have been known and used for many yearsfor a variety of-purposes. The term creosote oils therefore, refers to avariety of oils of extremely complex chemical composition and physicalproperties, and these attributes vary markedly with the source of theoil, the distillation process by which it was recovered and otherfactors concerning its history. For example, the coal gas tars and cokeoven tars are usually distilled to produce at least two fractions, alight or low boiling fraction, a heavy or high. boiling fraction, andsometimes a medium fraction as 'heterocyclic nitrogen bases, anaphthalene fraction, etc.

The oils marketedas creosote oils may be constituted of all or part ofthe original distillate, or, as is often the case, they may be blends ofdistillates which have been treated in other recovery operations. Theseextremely complex mixtures are sold for a variety of uses, one of thelargest and most important of which is for wood preservation bytreatment of the wood with the creosote oil by suitable methods, whichmay include brushing, spraying, immersion, or the like, with or withoutthe aid of vacuum or pressure treatments.

If the original distillation of the tar has been carried out to form ahard pitch, e. g., if the tar has been heated at temperatures up toabout 355 C. or above to remove a large percentageof the high'boilingoils from the residue, the proportion of such high boiling compounds inthe resulting heavy and medium oils will be high, and such'compounds mayalso be present to some extent in the lighteroils as well.

Such crystallizable compounds occur as mixtures of a variety ofcompounds including] anthracene, carbazole, phenanthrene and the like-They'are usually colloquially characterized as anthracene salts, and arevaluable by-products, useful in the manufacture of dyes and the like.Many creosote oils, especially oils containing high percentages ofcrystallizablecompounds, although fluid' when freshly prepared, oftenprecipitate a portion of the crystalline anthracene salts, on storage orshipment under prevailing industrial "conditions, especially in thewinter months when temperatures are low.

ice

Creosote oils of the character described have been treated or clarifiedin the past to produce oils of higher liquidities by a number of methodsincluding storage forlong periods during which crystallizable compounds,the anthracene salts, precipitated from the oil and settled to thebottom of the storage vessel. Another prior clarification methodinvolved slowly cooling the oil in large agitated vessels equipped withinternal cooling coils, followed by separation of the crystallizedsolids from the oil, usually by centrifuging. Another method utilized anoutside heat exchanger with pump circulation to effect slow cooling ofthe oil. In still another method, the oil was passed through a tank ortower equipped with exterior cooling means and rotating side scrapers toremove the crystals from the walls of the tank, and the resultingcrystal slurry was passed to a centrifuge to separate crystals frommother liquor. All of these processes had the disadvantage of high cost,either for storage or for refrigeration, and, due to the tendency of thecrystals to coat the cooling surfaces and form an insulating layer whichrestricted passage of heat to the cooling medium, made the processesemployiug refrigeration largely impracticable Eifortsto avoid thedisadvantages of crystal build-up on the cooling surfaces by increasingthe rate of cooling (shock cooling) as by increasing the temperaturediiferences between oil and cooling surface, or by increasing agitationor circulation rate, resulted in the formation of extremely finecrystals which were difficult or impossible to separate from the oil bypractical means. Moreover, while it has been known that certain liquidhydrocarbons, including molten naphthalene, could be cooled to the pointof crystallization by contacting them with immiscible liquids such aswater, such cooling methods.

have not been considered applicable to the cooling of creosotes becauseof the strong tendency of the creosotes to occlude water in emulsion orother form and thus make difiicult the subsequent separation of water toproduce the required water-free product.

It is an object of the present invention to provide a process forclarifying creosote oils which avoids the disadvantages of the prior artprocesses.

A further object is to provide a continuous processfor thecrystallization and removal of crystallizable components from creosoteoils to such an extent that the resulting oil remains fluid underprevailing industrial-conditions of storage and shipment.

A still further object is to provide a process for continuouslyproducing clarified creosote oils of a Wide range of desired liquiditycharacteristics.

A still further object of-the invention is to provide a process forlowering the limpid point of a creosote oil.

A still further object is to provide a process by which creosote oils oflow fluidity may be processed continuously for the production of highfluidity oil and valuable anthracene salts.

A stillfurther object is to provide a process for rapidly coolingcreosote oils to produce anthracene salt crystals of relatively large,free draining, easily separable character.

These and other objects are accomplished according to my inventionwherein countercurrently flowing streams of creosote oil and water arebrought into direct heat exchanging relationship with each other in acontacting zone under such conditions that partial crystallization of a.portion of the oil is eifected, and large free draining crystals areformed.

Contacting of the mutually immiscible oil and water may be effected,according to. my invention, in any suitable manner which insures thedesired degree of heat exchange within temperature and time rangeswithin which large, tree draining crystals are formed of componentswhose removal will leave a resulting creosote oil of the desiredliquidity characteristics.

Liquidity characteristics of creosote oils are customarily measured interms of the so-called limpid point (out), which is the temperature atwhich the first crystals appear when the oil is cooled from a highertemperature. Another characteristic sometimes used in evaluatmg cresoteOils is the limpid point (in) which is the temperature at which the lastcrystals of a cresote oilcrystal slurry dissolve when the slurry isheated. Whenever the term limpid point is used in the trade Withoutqualification, it usually refers to limpid point (out), and will be soused in the present specification. This temperature of limpid point(out), is usually used as synonymous with the temperature of completeliquidity.

Thus when a creosote oil is cooled from a temperature which is above itslimpid point (out) temperature, to a temperature below such point,crystals will form, whose separation results in an oil of lower limpidpoint. Continued cooling and separation .of crystals will continue tolower the limpid point of the resulting oil still further until thedesired limpid point lowering has been effected.

In carrying out the limpid point lowering of creosote oils according tomy invention, water which is at a tem perature below the Iirnpid pointout of the creosote oil to be treated, and which is preferablysubstantially free of dissolved gases under pressure, is introducedcontinuously into a body of creosote oil in such a manner as to avoidattaining the critical injection velocity which would causeemulsification, and to cause gentle, smoothly flowing streams orglobules of water to form which pass slowly through the oil, cooling theoil below its initial limpid point and causing crystallization of atleast a portion of the components. In a preferred embodiment of theinvention, hot creosote oil is continuously fed into a vertical columnof creosote oil, and, due to its greater specific gravity, passesdownwardly through the ascending streams of water droplets during whichtime a portion of its heat is absorbed by the water. Crystallization isusually initiated somewhat below the point of introduction of thecreosote oils, and crystal formation and growth continue during thepassage of the oil through the column, the cooling rate decreasingsomewhat as the creosote oil moves down the column, allowing time forcrystal growth in the cooler, more viscous creosote. After contact ofthe oil with thewater is complete, the resulting oil-crystal slurry iscontinuously withdrawn to a slurry receiver. The crystals may beseparated from the slurry in any desired manner, for example bycentrifuging or filtering the slurry immediately, or if desired by firstallowing time for settling of the crystals, followed-by decanting thesupernatant oil, and mechanically separating the crystals from thethickened slurry, aided if desired, by washings with hot water toseparate entrained oil from the crystals.

A particular advantage of the process is that creosote oils attemperatures.considerably above their limpid point temperatures, forexample at 80 to 90 C. or higher. as they come from the stills orblending vessels may be fed directly to the clarifying tower without aseparate cooling step and the hot creosote oil may be cooled down to thepoint of initial crystallization (its limpid point out temperature)rapidly by contact with the ascending cooling water and by thesupernatant pool of water which collects above the heavier creosote oil.In such cases the process combines a two stage cooling andcrystallization elfect in. a single continuous process; the first stagebeing the rapid cooling of the hot creosote oil to its limpid pointtemperature, the second stage being the controlled slow cooling of theoil'during the crystallization stage.

The resulting creosote oil will possess a limpid point which is lowerthan that of the original. oil, the degree 4 of lowering being dependenton conditions used, as explained hereinafter, and will be substantiallyfree of water. The recovered crystals of anthracene salts may be furtherpurified and resolved into their component compounds includinganthracene, carbazole, etc.

The water which has been used to effect the direct cooling andcrystallization of the creosote oil is substantially uncontaminated andmay be reused, aftercooling, for further creosote oil treatments.

Any of the class of oils known as creosote oils may be treated accordingto my invention to eliect a lowering of their limpid points and-toimprove their liquidity including so-called light, medium and heavycreosote oils. My invention is particularly adapted for use in treatingoils of this character which have specific gravitics greater than i, i.e., that areheavier than water, and is especially advantageous intreating the heavier oils resulting from carrying tar distillationstoharder pitches, and which oils thus have relatively high percentages ofcomponents boiling above 355 C. These latter oils cannot be adequatelyclarified by current clarification process to produce commerciallyacceptable creosotes which will remain fluid under industrial conditionsof storage and shipment.

While the creosote oils contemplated for treatmentment according to myinvention are extremely complex and have widely varying characteristics,they may be defined generally as distillates of coal gas tar or cokeoven tar or fractions or mixtures thereof having boiling ranges'predominantly within the range between about 20 C. andlabout400 C., andhaving specific gravitics of between 1.03and 1.18. Many of the lightcreosote oils boil or distill. completelywithin the range between about200 C. and about 355 C., while others; such as the so-called mediumand'heavy oils notably the creosote .oils from. hard pitch 'distillations,may contain up to 50% of components'distilling at 355 C. and above.

The water used in direct coolingof the creosote oil should preferably besubstantially free of dissolved gases, such as air, under pressure. Ifsuch gases are present when ihewater'is introduced-in thecreosote oilcolumn, the releaseof'pressure at the timeof such introduction will tendto liberate gas bubbles within the body of the creosote oil where theymay become trapped, so lowering the effective density of the oil that itmay cease to flow by gravity .throughzthecolumnr If water as received atthe. process site contains such dissolved gases under pressure, it mayreadilybe released by suitable means. as by vacuum degassing orby simplyreleasing the water into an. open. tank to release excess gas underpressure.

The cooling water used. should preferably be introduced.into,'and;'caused. to fio'tv upwardly through the columnof creosote oilin gentle smooth-flowing streams of globules (as distinct from jets orsprays), to avoid emulsion formation. .Thissmooth flow may beaccomplished,-for example, by providing water distributor openingslargeenough to avoid the critical injection velocities responsible for.emulsification, and, to avoid clogging of the water inlets withanthracene salts it may be advantag'eousto orient: theinletsin thedirection of the creosote flowpfonexample to;locate.them on the underside of a pipeorsparger type distributor.

The choice of operating. conditions will. of course depend on. thefinallimpid.pointcharacteristics desired in theclarified oil- .Anyconditions' which reducethe temperature of'theo-il froma temperatureabove its limpid point (out):to.a temperature below the limpid point(out). will .eftectsome crystallization and consequent limpidpointwlowering of the. oil obtained on separation of the-crystals, andsuch conditions, therefore, are within the scopexof myzinventiomIn:clarifying..creosote oils for commercial use, it is usually.desirable to ciiect a lowering of thelimpid point of the oil to. avaluewhich will insure. maintenance ofdts' liquidity under the particularindustrial conditions to which the 0il:.Wil1:.b6 subbe sufiicient toreduce the limpid point out to about 10 C., although creosote oils forspecial purposes maybe required to remain crystal-free at 5 C. or evenlower temperatures. For other purposes, less drastic liquidityrequirements are imposed. Conditions which can be controlled to effectthe desired limpid point lowering and which are interrelated are (a) therelative initial temperatures of creosote oil and water, (b), the ratesof water and creosote flow and (c) the initial limpid point of thecreosote oil.

The quantity of water needed to promote optimum conditions forcrystallization is surprisinglysmall. It depends on the aboveinterrelated factors chiefly (a) the rate of creosote flow (b) thetemperatures of the water and of the creosote supplied to thecrystallizer, (c) the temperature at which crystals start to form whenthe creosote is cooled (i. e. the limpid point out) and-(d) the degreeof limpid point lowering to be effected, a quantity of water equal tobetween about A and about the weight of creosote oil usually beingsufiicient.

The respective initial temperatures of the countercurrently flowingcreosote oil andwater employed, will depend on the characteristics ofthe creosote oil being treated and on the characteristicsdesired in theclarified oil product, as well as on the rate of flow and contact timeof the two liquids. The initial temperature of the creosote oil will beat least equal to its limpid point out temperature, usually somewhatabove. I d

The initial temperature of the water will be below the limpid point ofthe particular creosote oil, and enough below, to effect the desiredlimpid point lowering under the conditions of operation. Temperaturesdown to about C. may be used.

The highest temperature present in the contacting zone will be at aboutthe point of creosote oil introduction, and the upper temperature limitin the effective crystallizing zone will desirably be maintained onlyslightly above the temperature at which crystallization starts in theparticular oil being clarified, i. e. the so-called limpid point (o'ut)of .the oil. Temperatures appreciably lower than limpid pointtemperatures at this point, tend to promote the formation of finecrystals which .are difiicult to separate from the oil. Temperaturesappreciably above limpid point temperatures at this point areunnecessary and wasteful of heat exchanging space 'and media in coolingthe oil to its limipid point temperature.

Temperatures at any given point in the contacting zone will dependon theinitial temperaturesof the contacting liquids, the length of thecontacting zone, and the relative flow rates of the liquids. Y

The cooling rate of the creosote oil is importantin producing large,free-draining crystals which can readily be removed from the clarifiedcreosote oils. One of the primary difficulties which has preventedadoption of the rapid cooling processes in the past is the 'tendency ofsuch processes, involving large temperature differences between oil andcoolant, to produce extremely fine crystals which weredifiicult orvirtuallyimpos'sible to'separate from the viscous creosote oils byreasonably ptacticable methods. I

In the process of my invention, even in cases where creosote oils athigh temperatures are introduced into the heat exchanger,crystallization is initiated slowly in the upper portion of thecontac'ting zone where the cool ing water is at a temperature below thelimpid point" (out) of the creosote oil but not sufficiently below tocause formation of large quantities of fine crystals, preferably notmore than about 5 C. below thelimpid point:

of the particular creosote oil, usually about to C. below. Such crystalsas are formed, act as nuclei for crystal growth as the creosoteisfurther cooleddurin its passage through ry'sta li i s zone- The, coolingrate in the crystallizing zone, therefore,

6 will'be slow enough to prevent crystallization in the fornt of fine,virtually inseparable crystals, but rapid enough so that clarificationof the oils may be effected inperiods appreciably shorter than haveheretofore been possible, a temperature drop of between about 6'. C. andabout 15 C. per hour usually being satisfactory.

In general there appears to be a minimum retention time, which mayvarywith the particular creosote oil,

' necessary to result in the formation of satisfactorily large crystalsfor ready separation from the oil in commercial equipment. In general aminimum of at least about 3 hours is required, a period between about 3hours and about 6 hours usually being sufficient if final temperaturesof the cooled creosote oil are not taken below about 20 C. Longer timesare required if lower temperatures are to be attained.

The temperature range through which the creosote oils are cooled willvary somewhat depending on the final limpid point desired in theclarified creosote oil. Cooling of creosote oils from above their limpidpoint out temperatures to a point of at least about 20 C. below theirlimpid point out temperatures results in substantial im-. provement inthe liquidity of the oil and in many cases.

desired. In general the final limpid point will be found to beappreciably lower than the temperature to which the creosote is cooled,according to the process of my invention, by as much as between about 10and about 20 C. Thus, to produce a creosote oil having a limpid pointbetween about 5" C., and about 10 C., it is usually sufficient to coolthe creosote oil toabout 20 C. If a lower final limpid point is desired,lower final cooling temperatures may be employed.

Initial limpid points of the various creosote oils adapted to beclarified according to my invention range from about C. to'as low asabout 40 C. itis usually sufficient for commercial purposes to reducethe limpid point of the oils to between about 5 C. and about 10 C. toproduce oils whichremain liquid under conditions, of industrial storageand shipment; Such oils as are produced from hard pitch distillationsusually have limpid points (out) between about 80 C. and about 60 C. andthus require controlled cooling througha temperature range of amaximum'of about 60 C. usually of about 40 C. or less, for example fromabout 70 C. to about 20 C., and in these ranges cooling'rates' averagingbe- .tween about 6.5" C. and about 10 C. per hour have been foundsatisfactory.

Thus, startingwith the desired minimum retention time necessary to formreadily separable crystals, and using water at an entering temperaturesuitable to produce the a desired final limpid point'in the clarifiedcreosote oil as explained above, corresponding factors may readily be Icalculated for use in various sized equipment according to the followingequation.

Retention Time (Hours) Height of crystallizing Volume of creosote perzone (inches) unit of length(gals/in.) Rateof creosote flow (gals/hr.)

in the drawing, 10 represents a well insulated cooling tower providedwith a creosote oil inlet ll near the top of the tower and a water inlet12, near the'bottom of the tower. The bottom. 13, of the tower, whichmay be rounded or conical, is equipped with an outlet 14, connected to adischargepipe 15. The discharge pipe'15 may be connected" either-to a.discharge' leg 17. which-in turn connects through valve 16b, by means:of overflow pipe 18 with .settling tank 19; or, it may be connecteddirectly, through valve 16a and pip'eZO with settlingtank 19. At theupper end of the tower, a water overflow pipe 21 adjustable by means ofa swivel 21a is positioned in water layer 22 above the creosote oillevel 23 for removing the water after it has passed through and abovethe creosote oil column.

EXAMPLES In the examples which followapparatus of the characterdescribed above was used in which the insulated tower was 6 inches indiameter by 19 feet high. Runs of 30 to 60 hours duration were made oneach of six different creosote oils (oils 1 to 6 inclusive).

In carrying out the runs the crystallizing tower was filled aboutthree-quarters full of creosote which had been previously clarified. Thelevels were then permitted to equalize in the tower and leg. Thecreosote pump was started, feeding hot creosote into the crystallizingtower through a short nipple in the side wall extending into the towerat a point about 16 feet above the water inlet and two feet below thewater overflow. The creosote feed was controlled to give a downward flowin the tower of three to four feet per hour. Cooling water at 8-20 C.was started. and the rate adjusted as required to maintain desiredtemperature gradient. Water was introduced through a single one-halfinch nipple on the side wall, extending to the center and turneddownward, at a level approximately one foot from the bottom of thetower. The distance of 16 feet between water and creosote inlet pointsfixedthe effective cooling height of the unit. With,- in a few secondsafter starting the water into the tower it separates and collects in .apool on the surface of the creosote. When the rise in level in thetower'is sufficient to compensate for the greater density of the coolercreosote in the discharge leg, the latter overflows and discharges thecooled slurry to the receiver. The water overflow level of the pool ontop of the creosote was adjusted to maintain this equilibrium with awater layer depth of 6 to 18 inches. A one-half inch nipple fordischarge of water was located above the creosote oil-water interface toavoid removing the creosote film on the surface.

Occasional adjustments of the'water discharge nipple were necessary tocompensate for gravity changes in the creosote and maintain the desiredwater layer depth and correspondingcreosote oil levels in the tower. Asmall interface float (not shown), responding to creosote level changesonly, guided these adjustments. By lowering the water level (decreasingthe height of liquid in the tower) the creosote level would rise,decreasing the depth of the water layer. Best results were obtained whenthe fresh hot creosote was introduced into the creosote zone in thecrystallizer and not into the water layer. About three hours afterstarting, the creosote collected up to that time representing theinitial filling charge was withdrawn from the receiver and stored tostart the next run. A few fine crystals were usually found in thiscreosote near the change period. A period of-two to three hoursoperation, after the starting creosote 'charge had been displaced, wasusually suflicient to bring the crystallizer to normal. conditions,requiring very. little attention beyond themainte: nanceof creosote andwater flows to the unit and disposal of thecooled slurry from thereceiver. The practice followed in shutting down was to stop the feedand water pumps, allow about 30 minutes to complete the separation ofwater and creosote in the unit, and then drain the creosote back to thefeed tank. By stopping the creosote pump only, the body of creosote inthe crystallizer could be cooled and discharged to the regular receiversby gradual displacement by the cooling water.

The creosote S1l1l'IiCS.W1'ithlCkIld in a. 22-inch diameter drum with acone bottom. The'flow of slurry from the: continuous crystallizerentered through a feed-pipe extending downward in thedrum to the-top ofthe-cone; Thickenedslurry containing 10 to 20 -percent solids waswithdrawnfrom the bottom of the cone at hourly intervals. Clarifiedcreosotewas recovered continuously (except for brief periods after eachunder-flow) through side arm arrangements around the top of the drum andjust below the creosote surface, preventing any water that collected onthe thickener from discharging with the water-free clarified creosote.

The recovery of creosote was completed on a 26-inch diameter perforatebasket suspended centrifuge. The feed slurry of 10 to 18 percent solidscontent was stored in a IOO-gallon agitated vessel installed above thecentrifuge.

Wire filter cloths of 30 x 30 square mesh per inch were used as a filtermedium in the centrifuge and gave good filtration rates and were freefrom plugging by greases and waxes present in many of the creosotes.Sturdier screens such as the 12 x 64 mesh per inch Dutch weave also givegood results.

The basket was brought to loading speed of 750 R. P. M.(corresponding toa centrifugal force of 200 times gravity) and the feed valve openedfull. Filtration was rapid for'two'to three minutes, beforesedimentation and compression of the crystals decreased the filtrationrate. Frequently, the basket speed was increased near the end of theloading cycle to maintain the filtration rate and complete the fillingof the basket. Loading times ranged between five and eleven .minutes forthe various creosotes. The installation of a multi-hole nozzle plate onthe feed pipe to distribute the slurry over the filter screen preventedsedimentation in the bowl and aided in filling an evenly loaded basket.

After loading was completed, a whizzing cycle of six to twelve minutesat 1,500 R. P. M. (800 times gravity) was suflicient to drythe cake. Thecrystals retained 10 to 20 percent of creosote as determined by pressingat 6,000 pounds pressure between absorbing paper.

Improved creosote yields were obtained by washing the 60 to 70 poundload of filter cake in the centrifuge basket with 150 to 175 pounds ofwater at to C. Washing required about two minutes to four minutes. Theinitial drying time (after loading) was reduced when washing was carriedout so that the overall cycle was not increased appreciably.

The washed salt retained only two to four percent of residual creosote.This creosote about one gallon per load, separated practicallycompletely from the wash water in one to two hours.

The physical characteristics of the creosote oils used in runs 1 to 6respectively are given in Table 1 together with the physicalcharacteristics of the clarified oil resulting therefrom after removalof the anthracene salt" crystals. Of these oils Nos. 1 and 2 are medium"oils, No. 3 is a heavy oil, No. 4 is a special light oil, No. 5 is acarbolic oil residue (a light oil) and No. 6 is a light oil.

Table No. 1.-Physical characteristics of creosote oiLr used, in Examples1-6 OIL, NO, 1

Charged,

C larified, Percent Distillation, C Percent Over 355 Sp; Gr. 80 C./l5.5C LimIplid Point, 0.:

Out Water, Percent OIL N0. 6

Charged Clarified Distillation, 0. P

ercent Po cent OIL NO. 2 I

3311 1 0.0 0.0 0.3 0.0 o Charged Clarified, 23311890111 as a; 315-35533.1 28.5 o 355 (landover 17.3 19.4

Sp. Gr.,15.5 C./15.5 0 1. 031 1. 084 0 Limpid Point, 0.: 1 In 72 39 3- te4 24 Water, percent .4 08 01 34.5

1.134 v Operating data showing the respective flow rates andinwatgnpement 58.1 1 itial temperatures of creosote and water andtemperatures f f at various locations within the crystallizing zone aregiven in Table 2 below, zero location being a point just above that atwhich crystallization is initiated.

Table No. 2--0perating data oils 1-6 Temperatures in C. at various TowerLoca- Flow Rate tions (Inches from oil inlet) Within Crystal- GallonsPer T lizlng Zone Hour R m 011m. 9 .3

Hours 5 167 119 71 24 0 g Creosote Water N0 Yields of creosote oils andanthracene salts from the several runs are given in Table 3 below.Distillation, 0. 1,2235%? 1333? Table No. 3.--Yields of creosote oilsand anthracene salts obtained in runs 1-6 $3 33 l2 3'2 5 Percent 235-2701.7 4.7 322:; a: 13-2 Gilt/fir- 355 o. and oviIIIIIIII 5212 5319 Salt itG r 15. 5" (I /655 0 1. 160

lmpl 01H .2

mm 70.0 220 59 4.7 4.7 95.3 60 7.3 9.7 90.3 0 0 59 4. 3 10. 5 s9. 5Water, P9109r 35 4.4 0.1 93.9 40 4.6 9.4 90.6 OIL No. 4 5.4 7.4 92.9

Distillation 0 Charged, clar The process of my invention prov1des dstmct advan- Percent Percent tages over prior art processes of creosoteoil clarificatlon and limpid point lowering, in that it provides a rapid0.0 0- 55 process for obtaining high yields of limpid creosote oil, 1.33.5 1 h h 14.5 1&7 eavmg lit e or no res1 u 01 in t e ant racene salts(1% or less); It is a commercially practicable, rela- 355Qand overtively"inexpensiveprocess; it is adapted to continuous Sp. G r., 15.5O./15.5 C 1.11 operation, with reuse of all process waters, andtherefore Luupld Point, C.2 1 d In 57 mo 50 presents no waste isposa proems, an 1 1s app me e w 0111 00 8 05 8 to a wlde variety of creosote011s to produce greater or.

a men 'i lesser degrees of limpid point lowering at will.

While the above describes the preferred embodiments OIL NO. 5

of my invention, it W111 be understood that departures may be madetherefrom within the scope of the specification on e Clarlfle mstmatwn'o Pei-Eng Percen and 61311115- I claim: 0-210 0.0 0.0 1. A process fortreating creosote oils to improve their g-g liquidity which comprisescausing countercurrently flow- 270-315 42.0 32.5 7 ing creosote oilhaving a limpid point out of at least g ggi over 3:3 2:? about 40 C. andwater to contact each other in direct Sp. Gr.,15.5 (%./15.5 C 1.096 heatexchanging relationship in a contacting zone whose fgifi'ff: 8H0 24temperature ranges from an upper limit which is above Out 68.0 9 thelimpid point out temperature of the oil to a lower limit which is atleast about 20 C. below the limpid point out temperature obsaidaoil,whereby free draining crystals are formed, and-separating-the crystalsfrom theroil.

ZSAprocess'for clarifying creosote oils to improve their liquidity whichcomprises causing countercurrently' flowing creosote oil having'alimpid"point'out of. at

least about 40 C. .and water. to. contact-each .other:- in:

direct heat exchangingrelationship in'a contacting zone whosetemperature rangesfrom an upper limit which is above the limpid pointout"temp'erature of the oil tobe clarified to a lower limit which is atleast about 20 C.. below the limpid point out temperature of said oilcomponents are formed, said contact of oil and water taking place over aperiod of time sufficient to produce large tree draining crystals, andto reduce the temperature of the creosote oil from above its limpidpointout temperature to a least about 20 C. below its limpid. point out"temperature and-separating the clarified oilfrom the resulting:crystals.

ture of the oil, whereby crystals of a portion of the oil 4. A processfor clarifyingcreosote oils to improve their liquidity which comprisescontinuously passing water upwardly through, and in direct heatexchanging contact with, a column of downwardly flowing creosote oilhaving an initial limpid point out between about 80 C. and about C., theinitial temperature of the oil being above its limpid point out, theinitial temperature of the water being between about 0 C. and about 20C., whereby free draining crystals of a portion of the oilcomponents-arefoimed.

5. A process for clarifying creosote oils to improve their liquiditywhich comprises continuously passing water upwardly through,l andv indirect heat exchanging contact with, a column. of downwardly flowingcreosote oil havingzan initial -.limpid pointout between about C.and'about 40'-C.,Ithe'intial' temperature of the oil being above itslimpid point out, the initial temperature of the-water beingbetween'about 0 C; and about 20 0., whereby crystals of a portionof theoil components are formed, 'saidcontact-ofoil-and water taking placeover a period of time of at least about 3 hours to produce large freedraining crystals, and at a rate of flow to produce cooling of thecreosote oil at a rate of between about 6.5" C. and about 10 C. per hourfrom its limpid point out temperature to a final temperature at leastabout 20 C. below its limpid point out temperature, and separating theclarified oil from the resulting crystals.

References Cited in the file of this patent UNITED STATES PATENTS271,080 Krells Jan. 23, 1883 2,163,581 Boyd June 27, 1939 2,340,168Allott et a1 Jan. 25, 1944 2,458,505 Denig Jan. 11, 1949 FOREIGN PATENTS172,937 Great Britain July 13, 1922 383,674 Germany Nov. 8, 1923

1. A PROCESS FOR TREATING CRESOTE OILS TO IMPROVE THEIR LIQUIDITY WHICHCOMPRISES CAUSING COUNTERCURRENTLY FLOWING CREOSOTE OIL HAVING A "LIMPIDPOINT OUT" OF AT LEAST ABOUT 40* C. AND WATER TO CONTACT EACH OTHER INDIRECT HEAT EXCHANGING RELATIONSHIP IN A CONTACTING ZONE WHOSETEMPERATURE RANGES FROM AN UPPER LIMIT WHICH IS ABOVE TEH "LIMPID POINTOUT" TEMPERATURE OF THE OIL TO A LOWER LIMIT WHICH IS AT LEAST ABOUT 20*C. BELOW THE "LIMPID POINT OUT" TEMPERATURE OF SAID OIL, WHEREBY FREEDRAINING CRYSTALS ARE FORMED, AND SEPARATING THE CRYSTALS FROM THE OIL.